Latch bolt mechanism

ABSTRACT

A latch mechanism is provided for use with a bolt cooperating with an electric strike in a door lock. The latch mechanism attached to the bolt comprises a latch, a cam member for caming a keeper to a noninterferring position with the latch, and a keeper for moving to an interferring position with the latch on closing and locking the door.

United States Patent 1191 Horgan, Jr.

LATCH BOLT MECHANISM William J. Horgan, Jr., Pittsburgh, Pa.

Blumcraft of Pittsburgh, Pittsburgh, Pa.

Filed: Feb. 3, 1972 Appl. No.: 223,185

inventor:

Assignee:

U.S. c1. 292/66, 70/151 R, 292 5,

292/223 161. c1. E05c 5/00, E05b 55/00 Field 6: Search 292/219, 224, 5, 292/6, 7, 40, 52, 64, 65, 66, 92, 21, 191, 192; 70/151 R References Cited UNITED STATES PATENTS 2/1966 Check 70/151 R 3,543,547 12/1970 Sugiyama 292/34l.l6

3,480,314 11/1969 Robinson 292/64 3,359,027 12/1967 Schlage et al.... 70/151 R 3,583,740 6/1971 Armstrong 292/21 Primary ExaminerRichard E. Moore Assistant Examiner-William F. Pate, Ill Attorney-Henry N. Paul, Jr, et al.

[57] ABSTRACT A latch mechanism is provided for use with a bolt cooperating with an electric strike in a door lock. The latch mechanism attached to the bolt comprises a latch, a cam member for caming a keeper to a noninterferring position with the latch, and a keeper for moving to an interferring position with the latch on closing and locking the door.

6 Claims, 6 Drawing Figures LATCH BOLT MECHANISM BACKGROUND OF THE INVENTION This invention relates todoor locks and latch mechanisms and in particular, to a jimmy proof latch mechanism for use with a vertically operated bolt in conjunction, most preferably, with an electric strike.

In the prior art both vertically operable dead bolt mechanisms and electric strikes are well known.

Its an object of this invention to provide a latch mechanism for use with such a bolt in order to make said lock jimmy proof.

This and other objects of the invention will become apparent from the following description with reference to the accompanying drawings.

SUMMARY OF THE INVENTION The present invention comprises a latch bolt mechanism having a latch, a cam and a keeper. The position of the keeper is regulated by the cam. The three elements cooperate to provide a jimmy proof bolt portion of a lock.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of a portion of a door locked in a frame and having mounted thereon a latch bolt mechanism in accordance with the preferred embodiment of this invention in the locked condition with.

an electric strike;

FIG. 2 is a foreshortened vertical section taken as indicated by the lines and arrows 2--2 in FIG. 1;

FIG. 3 is a partial elevation taken as indicated by the lines and arrows 33 in FIG. 2;

FIG. 4 is a vertical section taken as indicated by the lines and arrows 4-4 in FIG. 1;

FIG. 5 is a view similar to FIG. 2 wherein the door has-been opened, showing some of the'parts delineated in FIG. 2, in alternate positions and in less detail; and

FIG. 6 is a view similar to FIG. 5 showing the parts in a transitory alternate position upon closing of the door.

DESCRIPTION OF THE PREFERRED EMBODIMENT Although specific forms of the invention have been selected for illustration in the drawings, and the follow ing description is drawn in specific terms for the purpose of describing these forms of the invention, this description is not intended to limit the scope of the invention which is defined in the appended claims.

Referring to the figures,'in FIG. 1 the upper portion of the door designated generally 10 is shown in its environment in a closed position in a door frame designated generally 12. The view is a face view taken from the inside of a building and at the upper right hand corner is a door stop 14 attached in any suitable manner to the frame. Also attached to the frame is the fixed portion of an electric strike means 16. Electric strikes are known in the prior art and, for example, are produced by Folger-Adam, a well known manufacturer.

Mounted along the face of the door spaced in from operable. Such bolts and lock mechanisms are well know in the art and a portion of the bolt mechanism is shown in greater detail in FIG. 2, wherein it will be noted that the bolt 20 is operated by a lever 22 and a plurality of other levers which are connected to the lock mechanism (not shown). The bolt rides securely in the housing 18 on ball bearings 24. Upon appropriate movement of the lock mechanism, by for example a key, handle, or panic bar, the bolt 10 is retracted vertically within the housing 18.

In FIGS. 1 through 4 the door is shown in the locked condition in the door frame. The electric strike means 16 includes an electrically actuated strike 30 which can be released electrically and which operates, in part, as a function of the position of a tripper 32. (again, both of these parts are well known in the art and will not be described in further detail). In the position shown in FIG. 2 the strike 30 and tripper 32 are in a fixed locked position. In order to open the door the lock mechanism in the door frame housing 18 can be actuated as foresaid and the bolt withdrawn so that the latch 34 clears the strike 30; the latch being withdrawn within the housing 18, and the door swung open to the position shown in FIG. 5.

The springs 36 and 38 force the latch 34 and the cam 40, respectively, upwardly to the position shown in FIG. 5. The clockwise rotational movement of the latch and cam about their common mounting pin 42 is inhibited by the pin 44 at the end of the coincident arcuate slots in each of these members, designated generally 46. It is in this position that the principal function of the cam member 40 can best be described. It will be noted that the outer arcuate surface 48 of the cam continuously engages the upper tip of the keeper 50. This surface 48 is coincident, along a portion thereof, with the outer arcuate surface 52 of the latch 34, when viewed as in FIG. 5. Both surfaces (48,52) have the same radius from the axis of the pin 42. As will be noted in FIG. 3, the width of the keeper 50 is such that it takes up the entire slot 54 in which both the latch 34 and the cam 40 are-mounted. Accordingly, the surface of the keeper 50 can engage one or both of these members.

Both of these members (34,40) have radial terminal surfaces 71 and respectively, which are inset on a shorter radius than the outer terminal surfaces, as will be noted from a comparison of the figures. As the door is swung to a closed position, by moving in the direction of the horizontal arrows in FIGS. 5 and 6, the upper surfaces 60 and 62 of the cam 40 and latch 34 resepctively, engage the arcuate surface 64 of the strike 30, and act as followers on this arcuate surface so that they are cammed downwardly, so that the members 34 and 40 are cammed in a counterclockwise direction about the pin 42 as the door is closed. The arcuate slot 46 provides for free movement about the pin 44 against the oppositely directed forces of the springs 36 and 38. As this occurs the keeper 50 which had been riding on the surface 48 also begins to ride on the surface 52. As the cam 40 rotates further in the direction of the arrow A in FIG. 6 it clears the keeper 50 by virtue of its inner arcuate surface 70 which is recessed, leaving the keeper 50 in engagement solely with the surface 52 on the latch 34. Then as the door is finally shut, as shown in the transitory view in FIG. 6, the upper corner 72 of the latch 34 clears the lower terminal corner of the surface 64 of the strike 30 and the latch 34 begins to rise in a clockwise direction as shown by the arrow B in FIG. 6 under the force of its spring 36. Eventually it will engage the signal tripper 32, and the surface 52 will clear the end of the keeper 50. At that point the keeper will be rotated in a clockwise direction about the pin 74 by the action of the spring 76 which is mounted in a blind hole in the bolt 20, so that it will lie in the recessed portion of the latch 34 as shown in FIG. 2. The inner radial surfaces 71 and 70 define a space into which the tip of the keeper 50 can move. It will be apparent that in this position a downward force on the latch 34 will cause the latch to engage the upper end of the keeper 50 whereby the keeper will prevent further depression of the latch 34 and thereby prevent the latch from being jimmied opened by, for example, a tool inserted between the frame and the latch.

it will also be apparent from what has been described above that the principal function of the cam 40 is to move the keeper out of its interferring relation with the downward movement of the latch 34 on opening the door, otherwise the latch could not be moved to the position shown in FIG. 6. This is done on opening of the door when the spring forces the cam 40 from the position shown in FIG. 2 to the position shown in FIG. 5 and the rising cam surface 4% contacts the keeper 50.

It will be understood that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to explain the nature of this invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the following claims.

it will further be understood that the Abstract of the Disclosure" set forth above is intended to provide a non-legal technical statement of the contents of the disclosure in compliance with the Rules of Practice of the United States Patent Office, and is not intended to limit the scope of the invention described and claimed herein.

I claim:

1. In combination with a door, jamb, lock bolt and strike, an improved latch mechanism comprising:

i a. a movable latch means connected to said bolt for movement to an interfering position with respect to said strike when said bolt is in a locked condition, said latch means having a member with a cam surface thereon relieved along a portion thereof;

b. a keeper means for movement between an interfering position in said relievedportion of said latch member and a non-interfering position on said cam surface of said latch member; and

c. a cam means connected to said bolt, having a cam member with a cam surface thereon relieved along a portion thereof, said cam means functioning to move said keeper means to a non-interfering position with respect to said latch means on opening said door to permit said latch means to clear said strike on closing said door; said latch means thereafter moving to an interfering position as aforesaid with said strike, and permitting said keeper means to move to an interfering position with said latch means when said latch means and bolt are in a locked condition.

2. The invention of claim 1 wherein said members are pivotally mounted and can be pivoted so that said surfaces are coincident.

3. The invention of claim 2 wherein said keeper means comprises a keeper pivotally connnected to said bolt, and a spring contacting said keeper and biasing said keeper towards said members for engagement with the cam surfaces thereof, said surfaces being so positioned with respect to one another that they are not coincident when said latch means and bolt means are in the locked condition.

4. The invention of claim 1 wherein said cam surfaces are coincident when said lock bolt and latch means are moved to an open noninterfering position with respect to said strike, said keeper lying in engagement with the cam surface of said cam means member.

5. In combination with a door, jamb, lock bolt and strike, an improved latch mechanism comprising:

a. a movable latch means connected to said bolt for movement to an interfering position with respect to said strike when said bolt is in a locked condition;

b. a keeper means for movement between an interfering and non-interfering position with respect to movement of said latch means, comprising a keeper pivotally connected to said bolt, and a spring contacting said keeper and biasing said keeper toward said latch means for engagement therewith; and

c. a cam means connected to said bolt to move said keeper means to a non-interfering position with re spect to said latch means to permit saidv latch means to clear said strike on closing said door; said latch means thereafter moving to an interfering position as aforesaid with said strike, and permitting said keeper means to move to an interfering position with said latch means when said latch means and bolt are in a locked condition.

6. The invention of claim 5 wherein said keeper rides against said cam surfaces; said latch and said cam each being spring biased to extend outwardly away from said bolt toward said strike and each having a further surface thereon which acts as a follower when engaging said strike on closing said door; said cam surfaces and relieved portions being so proportioned and disposed with respect to one another that the following coacting relationship ensues: when said lock bolt is retracted with respect to said strike upon opening of said door, said cam and latch are fully extended and clear said strike; thereafter when said lock bolt is returned to its unretracted condition while said door is open, said latch and cam remain in their extended condition and the cam surface of said cam engages said keeper and in part lies coincident with the cam surface of said latch; then as said door is moving to a closed position, said further surfaces of said cam and said latch contact the surface of said strike and act as followers thereon and as said door is closed said latch and cam are pivotally moved to a first position wherein said keeper engages the cam surfaces of both said cam and said latch, and then to a second position where said keeper engages only the cam surface of said latch; and then as said door is fully closed the further surface of said latch which has been acting as a follower on the surface of said strike clears said strike and the spring biasing said latch forces said latch to extend from said bolt, and during such extension said keeper follows the cam surface of said latch until said surface clears said keeper at which point said keeper is spring biased into the relieved portion of said latch; said further surface of said cam which is a follower of the surface of said strike remaining in engagement therewith so that said cam is clear of said keeper, the relieved portion of said cam being so positioned that it is coincident, in part, with the relieved portion of said latch when said latch is in the locked position.

# 41 m m m 

1. In combination with a door, jamb, lock bolt and strike, an improved latch mechanism comprising: a. a movable latch means connected to said bolt for movement to an interfering position with respect to said strike when said bolt is in a locked condition, said latch means having a member with a cam surface thereon relieved along a portion thereof; b. a keeper means for movement between an interfering position in said relieved portion of said latch member and a noninterfering position on said cam surface of said latch member; and c. a cam means connected to said bolt, having a cam member with a cam surface thereon relieved along a portion thereof, said cam means functioning to move said keeper means to a noninterfering position with respect to said latch means on opening said door to permit said latch means to clear said strike on closing said door; said latch means thereafter moving to an interfering position as aforesaid with said strike, and permitting said keeper means to move to an interfering position with said latch means when said latch means and bolt are in a locked condition.
 2. The invention of claim 1 wherein said members are pivotally mounted and can be pivoted so that said surfaces are coincident.
 3. The invention of claim 2 wherein said keeper means comprises a keeper pivotally connnected to said bolt, and a spring contacting said keeper and biasing said keeper towards said members for engagement with the cam surfaces thereof, said surfaces being so positioned with respect to one another that they are not coincident when said latch means and bolt means are in the locked condition.
 4. The invention of claim 1 wherein said cam surfaces are coincident when said lock bolt and latch means are moved to an open noninterfering position with respect to said strike, said keeper lying in engagement with the cam surface of said cam means member.
 5. In combination with a door, jamb, lock bolt and strike, an improved latch mechanism comprising: a. a movable latch means connected to said bolt for movement to an interfering position with respect to said strike when said bolt is in a locked condition; b. a keeper means for movement between an interfering and non-interfering position with respect to movement of said latch means, comprising a keeper pivotally connected to said bolt, and a spring contacting said keeper and biasing said keeper toward said latch means for engagement therewith; and c. a cam means connected to said bolt to move said keeper means to a noN-interfering position with respect to said latch means to permit said latch means to clear said strike on closing said door; said latch means thereafter moving to an interfering position as aforesaid with said strike, and permitting said keeper means to move to an interfering position with said latch means when said latch means and bolt are in a locked condition.
 6. The invention of claim 5 wherein said keeper rides against said cam surfaces; said latch and said cam each being spring biased to extend outwardly away from said bolt toward said strike and each having a further surface thereon which acts as a follower when engaging said strike on closing said door; said cam surfaces and relieved portions being so proportioned and disposed with respect to one another that the following coacting relationship ensues: when said lock bolt is retracted with respect to said strike upon opening of said door, said cam and latch are fully extended and clear said strike; thereafter when said lock bolt is returned to its unretracted condition while said door is open, said latch and cam remain in their extended condition and the cam surface of said cam engages said keeper and in part lies coincident with the cam surface of said latch; then as said door is moving to a closed position, said further surfaces of said cam and said latch contact the surface of said strike and act as followers thereon and as said door is closed said latch and cam are pivotally moved to a first position wherein said keeper engages the cam surfaces of both said cam and said latch, and then to a second position where said keeper engages only the cam surface of said latch; and then as said door is fully closed the further surface of said latch which has been acting as a follower on the surface of said strike clears said strike and the spring biasing said latch forces said latch to extend from said bolt, and during such extension said keeper follows the cam surface of said latch until said surface clears said keeper at which point said keeper is spring biased into the relieved portion of said latch; said further surface of said cam which is a follower of the surface of said strike remaining in engagement therewith so that said cam is clear of said keeper, the relieved portion of said cam being so positioned that it is coincident, in part, with the relieved portion of said latch when said latch is in the locked position. 